Vehicle: 2007 Dodge RAM 1500, 4WD, V8-5.7L, VIN D, Automatic Transmission
Mileage: 146,000
Problem: DTC P0301 (#1-cylinder misfire)
Details: The truck drove in with the malfunction indicator light on. The first thing the tech did was to check for spark and injection timing. Both were correct. On recommendation of the Tech-Asist Consultant, the tech connected a scope and pressure transducer to number one cylinder to check compression.
In scope pattern, he noticed that the exhaust stroke pressure was rising significantly as if the exhaust valve was barely opening. After removing the bank one valve cover and cranking the engine over with the ignition disabled, the tech noticed that the number one cylinder exhaust rocker was hardly moving. Upon further inspection, he found that the lifter was completely broken (See good and bad pattern images).
Good – Flat exhaust pattern
Bad – High exhaust spikes
Confirmed Repair: The tech replaced the lifter and the engine ran perfectly after the repair.
The ALLDATA Tech-Assist team fields cases like this every day. See how Tech-Assist can help your shop save time and money with on-call diagnostic support from ASE-certified Master Technicians. More Tech Tips
Not an ALLDATA customer? For access to this valuable experience-based repair data and reliable OEM information, start a free trial today.
If you would like to read more articles like this one please subscribe to ALLDATA News.